The invention relates generally to a system for interconnecting structural members. More particularly, the invention relates to a system particularly well suited for joining structural members involved in the construction of furniture, such as by interconnecting a first furniture frame element perpendicular to a second furniture frame element with an interlocking joint formed by a substantially hexagonal tenon that inserts into a quadrilateral mortise and pivots into a locked position. The invention is also suitable for interconnecting structural frames for various types of buildings and similar purposes.
Many types of home furniture are constructed by joining a horizontal frame segment to a vertical frame segment, especially when the two segments are orthogonal to each other. There are many examples of this type of structure, such as shelving, drawers, bed frames, chair rails and stretchers, and cabinetry in general. Furniture makers form these joints by inserting an end on the horizontal segment into a channel on the orthogonal vertical segment. When the joint is a permanent connection, the furniture makers reinforce the joint with glue or other attachments means such as nails. When the joint is meant to be nonpermanent, such as when assembling a bed frame, the furniture manufacturer must rely on a joint that locks together, forming a structurally strong joint, but can allow the furniture to be disassembled. Traditionally, these joints are formed by a tenon and mortise, similar to the tongue and groove used when joining segments that are in the same plane, not orthogonal. In these systems, one segment has a least one female opening and the joining piece has a male piece that is inserted into the opening.
Many different structures for forming a joint using a tenon and mortise or tongue and groove have been proposed. Many shapes have been created for the tenon or tongue, including a beveled hook, a diamond, a square, and a beveled parallelogram. Some have an additional locking rib to catch onto a side of the groove or mortise. Similarly, many shapes to accommodate the mated tenon or tongue have been proposed for the mortise or groove. In addition to square, rectangular, parallelogram, triangular, and elliptical shaped grooves and mortises, a compound orthogonal channel in the shape of a cross has been designed for receiving a tenon or tongue. Others have proposed additional hardware to support the joint such as caps or hooks.
While these units may be suitable for the particular purpose employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter.